1. Field of the Invention
The present invention relates to an optical guide bar, a line light source device, a surface light illumination device, and a display apparatus adopting the same.
2. Description of the Related Art
Various types of light sources are being developed in accordance with the development of display apparatuses. A non-emissive type flat panel display apparatus such as a liquid crystal display (LCD) requires an illumination device to provide a surface light. The light source of the illumination device for providing the surface light can use a line light source such as a color cathode fluorescent lamp (CCFL) or a point light source such as a light emitting diode (LED) and an organic light emitting diode (OLED). The line light source shows an even light distribution in a length direction thereof. However, there is a limitation in the shortest length of the line light source, and thus, it is difficult to apply the line light source to small sized portable display apparatuses. Therefore, recently LEDs and OLED are commonly used as the light source in the small size portable display apparatus since they show high brightness while having a small size. In a case where a plurality of point light sources are used as the light source, a problem of uneven brightness over the entire surface of a display apparatus caused by bright lines and dark lines generated between the point light sources must be solved. Therefore, a line light source device for changing the light irradiated from the light source into the line light source is required. In addition, a surface light illumination device that changes the light irradiated from the line light source device into the surface light is also required.